Cascioli F Maierhöfer P Pozzorini S 2012 We introduce a new technique to generate scattering amplitudes at one loop. Traditional tree algorithms, which handle diagrams with fixed momenta, are promoted to generators of loop-momentum polynomials that we call open loops. Combining open loops with tensor-integral and Ossola-Papadopoulos-Pittau reduction results in a fully flexible, very fast, and numerically stable one-loop generator. As demonstrated with nontrivial applications, the open-loop approach will permit us to obtain precise predictions for a very wide range of collider processes. application/pdf https://sonar.ch/global/documents/146756 eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.108.111601 info:eu-repo/semantics/altIdentifier/pmid/22540459 info:eu-repo/semantics/openAccess Physical review letters. - 2012 Scattering amplitudes with open loops. http://purl.org/coar/resource_type/c_6501